Urgent help please, trouble with getMethod

Hi, Im been working with a project now, and have got stuck. Cant see what im doing wrong. Im supposed to make a Digital Thermometer. Right now im stuck on passing values from one class to another, been trying to use get methods.It seems like the value I get is 0 all the time. Have placed alot of sout lines and have seen that the values should be different from 0.

//This is the method that will be executed when the buttom show max is pushed
public void showMax() {
tempMaxInne = comp.getMaxInne();
tempMaxUte = comp.getMaxUte();
System.out.println("This is max insdie: " + tempMaxInne);
System.out.println("This is max outside: " + tempMaxUte);
}

The comp.getMaxInne(); will call the method from the compare class That looks like: